Such valves are used, for example, in explosion protection apparatuses in industrial systems where there is an explosion risk, for automatically preventing the penetration of pressure waves and/or flames from a system part where there is an explosion risk into an adjacent system part. In the case of explosion protection apparatuses, it is of critical importance that, when necessary, the passageway between two system parts, in general a transport pipe, is closed, sealed, as quickly as possible. The closing process must be completed before pressure waves and/or flames arrive at the closing point. To this end, a closing element is moved at high speed to the passageway to be closed, and is braked quickly on reaching the closed position.
EP-A-0 824 027 describes an explosion protection apparatus having a valve which has a pipe element with an opening in the wall, through which opening a slide can be pushed, from the outside, as a closing element into the pipe element which, in the closed position, closes the passageway. This valve is particularly suitable for transport pipes through which gases flow. If the gas flows are loaded with solid products, then there is a risk of solid particles collecting in the closing region which, on the one hand, can lead to the closure not being sealed and, on the other hand, contaminates the valve, which often means that costly cleaning is necessary when a product change takes place.